What are you plugging in , I've found my V60T6 has similar issue but they tested it ok, both my adaptor were no good, still not tried anything else.
I've found a large power block battery is way better for changing phone or DAC I use, I can use it a few times , take it in to charge it.
I'm considering dedicated power wires from battery instead of the lighter sockets, they are junk quality so probably that's the issue......